Change to/from synthetic oil ? [Archive] - Forum


View Full Version : Change to/from synthetic oil ?

10-01-2009, 10:19 PM
I have two questions on synthetic oil:

1) I changed to synthetic oil at 37,000 miles in my '99 Alero, which is now at 86,000 miles and had a lot of racing. Would it do any harm to put in regular oil for the Winter season, since it will be down for repairs a lot of the time, then switch back to synthetic next Spring?

2) My '03 Alero is long overdue for an oil change, has 25,000 miles on it. If I plan on racing this one, what is the latest mileage to let it get up to before changing to synthetic?

2000 GT Coupe
10-01-2009, 11:42 PM
This is not to be taken for gospel but I would think having synthetic in while its down might be better as time does not break down synthetic nearly as quickly as dino based does. But if you do decide to switch to dino I do not think it would be a problem, on the label of the synthetic bottles I have looked at it says you can mix with regular.

As to your 03 I think the motor should be well broken in by 25k I think switching would be no problem.

10-03-2009, 07:15 AM
I wouldn't be swirching from synth to regular I'd buy one and stick to it.

10-03-2009, 07:33 AM
You can switch as often as you like. That is an old fallacy about switching between oils. Yes, full syn is suppose to give the best protection, but I have found if I use full syn, I burn the crap out of it. I use a semi-syn 4X4 Quaker State oil. It's the one I recommend for any 3100 or 3400's. Do not deviate from 5/30 no matter what anyone says to you. It is what our oil ports and pump was designed to handle. Heavier oils will affect your emissions as well.